An electron is projected horizontally with a kinetic energy of 10...

Let the direction of motion of the electron be along the $+x$-axis, so $\vec{v} = v \hat{i}$.

Let the vertically upward direction be along the $+y$-axis, so $\vec{B} = B \hat{j}$.

The magnetic force experienced by a moving charge is given by $\vec{F} = q(\vec{v} \times \vec{B})$.

For an electron, $q = -e$. Substituting the values, we get:

$\vec{F} = -e(v \hat{i} \times B \hat{j}) = -evB(\hat{i} \times \hat{j}) = -evB \hat{k}$

In a right-handed coordinate system, if $+x$ is forward and $+y$ is upward, the $+z$-axis ($\hat{k}$) points to the left.

Since the force is in the $-\hat{k}$ direction, the electron will deflect towards the right.